Crucible supplier in Wellington?

[degrom]

Hi.

I am busy building a foundry and will soon be in need of a crucible to melt
aluminium.

Any body know of a supplier in the wellington Region?

Thanks.

[Fooman]

How are yah melting it? Induction, electrical or gas? I made my own electrical furnace, and made my own crucible out of a stainless steel mixing bowel and plenty of alumina paint.

There's furnaceworks in Upper Hutt - don't know if they do cruicbles. Try ringing Foseco in Akl/Chch.

Cheers,
FM

[davereid]

I made one from steel. I have found getting the furnace hot enough really difficult - I'm using air assisted LPG, it melts the aluminium OK but either the temperature is not hot enough, of my crucible conducts too much of the heat away, as the aluminium cools to quickly. Keep in tough with how you get on.

[degrom]

I am building a charcoal foundry... Its about 350mm in diameter and 500mm high. I found a source in Auckland that sells a 255mm(H) x 200mm(D) crucible for just over $110.

Its not a bad price I think. Just not sure if 25mm is going to leave enough room on the sides of the crucible... :)

[Pixie]

..... stainless steel mixing bowel

FM

That would be great for hot curries!
where do I get one?

[Slingshot]

What do you plan to do with this foundry of yours?

Would it be possible make shit like a head for a small 2stroke engine?

[Pancakes]

Mmmm, so the new thing is home foundries? What next? What are you guys making is the question really eh.

[geoffm]

For my foundry, I welded up a metal one from steel pipe. I believe you as supposed to put a wash on the inside to prevent iron disolving in the ali, but I never bothered and stuff was ok. These days with the welders, I tend to fabricate rather than cast stuff.
Go for gas - much easier and cleaner to use than charcoal. You can do brass and bronze with a good gas burner, if you have good insulation, and enough gas. See Forman Insulation fo rKaowool for the lining. I use it in my gas forge. There is a web site of a guy doing iron casting with a naturally aspirated gas burner.
Geoff

[degrom]

What do you plan to do with this foundry of yours?

Would it be possible make shit like a head for a small 2stroke engine?

Anything is possible these days!!! (Making a head might not be that hard but you will need all the tools like a mill to machine it to spec)

Main reason for having one is to save on material. Aluminum is very easy to recycle and there are heaps of scraps around. Funny thing is,have you seen the prices on new aluminum? (I thought petrol was dear!!!)

With casting you can cast the aluminum to a shape that is almost what you need and machine it to spec...

Why do I want to do it... You know how moth's are bedazzled by a candle. Well I get the same warm feeling when I think/talk/work with metal.(Bikes also tend to give me the same feeling)

[degrom]

For my foundry, I welded up a metal one from steel pipe. I believe you as supposed to put a wash on the inside to prevent iron disolving in the ali, but I never bothered and stuff was ok. These days with the welders, I tend to fabricate rather than cast stuff.
Go for gas - much easier and cleaner to use than charcoal. You can do brass and bronze with a good gas burner, if you have good insulation, and enough gas. See Forman Insulation fo rKaowool for the lining. I use it in my gas forge. There is a web site of a guy doing iron casting with a naturally aspirated gas burner.
Geoff

You have me thinking now.. Gas is a lot cleaner and easy to work with.

Thanks mate,you are a real inspiration!!!

[geoffm]

Have a look in a recent back issue of the Shed mag - Feb/ march 2007. THe sell back issues - Robin Overall did a great article on building a nice looking furnace
I had some plans in my archives for a furnace as well.
Google the "Mongo burner" - lots to keep you busy for a while, and without spending money. Someone is using one of these to melt cast iron.
If you crank up the burner, you will run into the limit of the regulator and bottle. A BBQ regulator has no pressure adjustment and is limited to the gas flow. Yes it works (mine used one) but ante up for a proper adjustable LPG reg from any welding shop. Adjustable pressure, guages etc are good.
The bottles may freeze if you do a big burn - after 20 misn or so, my forge will freeze a 9kg caravan bottle as you are drawing off more gas than the LPG can vaporise. Putting the bottle in water helps, Bunnings sells 12kg bottles, but the only real answer is biger bottles and more of them with a manifold. You will problaby be ok with aluminium casting but brass or bronze might be an issue.
Geoff

[davereid]

Thanks for the link Geoff but the forge bit is dead :

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The requested URL /~gmerryweather/edifice/The Edifice blacksmiths shop.htm was not found on this server.

Cheers Dave

[Fooman]

Electrical is the cleanest - gas heating still puts a lot of moisture into the melt - have to make sure you degas it well - nitrogen running through a graphite lance into the melt works well, better than the degassing tablets.

I was running a furnace off a single phase socket - was melting 2kg of alloy up to 710 °C in a couple of hours (about $1 worth of eleccy). Aluminium has a really high specific heat capacity so it requires a lot of engery to heat up.

I made the mistake of using a castable refractory for my furnace (was a sealed furnace pressurised with argon to increase melt quality and to do a bottom tap into the die) - not as good as kaowool, and it picked up a lot of moisture of the atmosphere and released it during the melting

[degrom]

Yes the LPG burner is not that hard to make... and they are pretty quick and clean to.

Basic plans for one (http://www.abana.org/ronreil/mongoburner2.pdf)

Regarding the freeze problem with the LPG cylinders,I have seen a setup with two 9KG LPG cylinders linked to supply gas to the burner. This will help a lot and I am sure if you link up to 12KG bottler you will be set for a while.(With aluminum anyway)

What concerns me more is getting a adjustable pressure valve with a gauges(This is to get the glasses flowing properly). They are pretty expensive at BOC. The guy at Well-Weld suggested I use a LPG adapter that will fit on an acetylene pressure valve. Not sure if that is a good idea or not...

[degrom]

Almost done with my gas burner for the foundry...

We are going up to Auckland the weekend,so while we are there I am going to pick up a crucible for the foundry. Not sure on the size yet,but I will see what the shop has to say.. :)

Here is a little movie clip of the burner at work... Its a bit dark but at least you can hear how it sounds..

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